The regime of President Bashar al-Assad was responding to the fact that ISIL “brought into Syria heavy weapons including tanks” captured from the Iraqi army.

Stop the bloodshed ... Peshmerga military direct traffic at a Kurdish Check point in Kalak, Iraq. Syria’s army has been pounding major bases of the Islamic State of Iraq and the Levant for 24 hours in Iraq.Source:Getty Images

In Raqa, the air force bombed the area surrounding ISIL’s main headquarters in Syria, as well as the group’s religious courts, said the Observatory, adding there were no reported casualties.

Photographs sent by activists in Raqa that could not be independently verified showed craters in the ground and rubble in front of the main gates of the headquarters, a former town hall.

On Saturday, the regime also bombarded ISIL’s headquarters at Shaddadi in Hasakeh, home to a frontier crossing from Iraq that is under the jihadists’ control.

Observatory director Rami Abdul Rahman said the strikes were the regime’s most “intense” against ISIL, and that they were being carried out “in coordination with the Iraqi authorities”.

The government in Baghdad has been gearing up for a counteroffensive against ISIL in areas where it and other Islamist militants have advanced in northern Iraq in the past week.

ISIL espouses a radical interpretation of Islam, and aims to set up a state stretching across the Syria-Iraq border.

On guard ... Peshmerga military make their way through a Kurdish Check point in Iraq.Source:Getty Images